I was solving this problem with the use of single hash and got wrong answer which means conflicts are arising. I've seen other users submission, they've solved it using double hashes, so I was wondering that can't this problem be solved using single hashing. Link to my submission:

As given in cp-algorithms.com for SCC, that we need to reverse the graph after sorting the vertices in decreasing order of exit time for finding strongly connected component so that we do not jump out into another SCC.

But instead of reversing the graph and traversing it can't we just traverse the original graph with increasing order of exit time ??

Please Help!! Thanks in advanced :)

Not sure if it'll help everyone, as many of you would be knowing these things....but here is a link for a good blog I found on the internet :

Get Started With The Sport Of Competitive Programming

And a curated list of awesome Competitive Programming, Algorithm and Data Structure resources, which can be found on :

List of algos, tutorials on language used also data structure, problem resources etc..

The latter has a list of problem classifiers which I found really helpful :) Thought to share with you all.. Kudos!! Happy Coding!!

I am not able to understand the editorial of the same. Please Help!! Link to the problem : http://codeforces.net/problemset/problem/343/A